In retrospect, neither player seems to have been given an egregiously large contract given the way the market has shaken out. But I generally don't like paying market prices for veteran relievers because relief pitchers tend to be more fungible than starting pitchers and everyday position players—and the latter two categories are harder to find.

For example, the Giants turned up Casilla on a minor league deal prior to 2010 after he had washed out by putting up a 5.96 ERA with the A's the season before. In three years with the Giants, he's put up a combined 2.22 ERA.

It's also worth noting that neither Casilla nor Affeldt projects to be the Giants closer in 2013. Manager Bruce Bochy may use them both to close occasionally depending on matchups, but it's more likely that Sergio Romo will retain the job.

Romo earned that role with his outstanding performance as the closer during the final month of the regular season and throughout the postseason. He saved all four of his playoff chances with a 0.84 ERA, and he nailed down all of his regular-season save opportunities in September and October.

Thus, it doesn't make sense to compare Casilla and Affeldt's contracts to those of Brandon League and Jonathon Broxton, as both were signed to be closers for their respective teams.

Instead, it's more instructive to look at the contracts handed out to setup men this winter using contractual data from Baseball Prospectus' Cot's Baseball Contracts.

The Cubs signed Shawn Camp to a one-year deal at $1.35 million and Kyuji Fujikawa to a two-year deal worth $9.5 million, with a club option for a third year. Tampa Bay re-signed setup man Joel Peralta for two years and $6 million with club options from 2015 through 2017.

The Pirates re-signed Jason Grilli to a two-year, $6.75 million deal to be their setup man, but after they dealt closer Joel Hanrahan, Grilli will likely become the team's closer.

The Brewers signed lefty relievers Tom Gorzelanny (two years, $5.7 million) and Mike Gonzalez (one year, $2.25 million). The Los Angeles Angels signed lefty reliever Sean Burnett to a two-year, $8 million deal with a third-year club option.

The largest contract given to a setup man was the Phillies' two-year, $12 million agreement with Mike Adams.

Thus, if the Giants were truly paying market prices for Affeldt and Casilla, they would have given them both two-year deals with club options for a third season at an average annual value of between $3 and $6 million. The Giants didn't overpay in terms of monetary value, but they probably guaranteed one year too many.

Given that the team is in win-now mode, it doesn't really matter if they have to slightly overpay to retain the guys they want. Casilla and Affeldt have both been very good in terms of run prevention with the Giants, so keeping both players in the fold makes sense.

The final thing to consider here is opportunity cost. Casilla was going to be in the fold for 2013 regardless because the Giants controlled him for one more season before he could become a free agent. However, the $8 million the team agreed to pay Affeldt next season could have gone towards upgrading left field, which appears to be the weakest spot on the roster.

Nick Swisherreportedly wanted to sign with the Giants, and he will make $11 million to play for the Indians next season after signing a four-year, $52 million deal with them. Had the Giants let Affeldt walk, they could have used the money allocated to him, plus the $2 million given to reserve outfielder Andres Torres, to make a run at Swisher. Upgrading from the Gregor Blanco-Torres platoon to Swisher in left field would have more than made up for the loss of Affeldt in the bullpen.

The Giants ultimately made retaining Affeldt more of a priority than upgrading left field. They won the World Series with Blanco starting in left for the final two months of the regular season and all of the postseason, so they probably figure that they can win it all with him out there again next season. He's also younger, much cheaper and a better defender and baserunner than Swisher.

The Giants didn't drastically overpay in re-signing Affeldt and extending Casilla. However, the resources used to retain Affeldt might have been better spent on a left-field upgrade.

Alas, I have the benefit of hindsight. But the Giants have to make these decisions in real time.